'A tonic for the Nation', The Festival was intended to cheer us all up after WW2, and incidentally to celebrate the centenary of the 1851 Great Exhibition. The symbol for the Festival was designed by Abram Games.
All the Festival buildings on the south bank except the Royal Festival Hall have since been demolished and replaced by other buildings forming the much-loved (British irony) arts complex known as The South Bank. The Festival of Britain was a nationwide event with two other sites in London: the Pleasure Gardens in Battersea and the Live Architecture Exhibition in Poplar, originally 'Neighbourhood 9' but then renamed the 'Lansbury Estate', after George Lansbury. Diamond Geezer , Caroline's Miscellany and A London Inheritance have all done good posts about this Estate. The City of London laid out a garden beside St Paul's, Festival Gardens.
The Festival Pleasure Gardens were installed in the northern part of Battersea Park. These included a water-garden and a tree-walk. There was also a fun fair on the section between Central Avenue and what is now the children's zoo. The BBC has photos of many of the items.
2019: Ian Visits spotted a Festival of Britain bench in an Essex village.
2019: In the 1957 film 'The Key Man' / 'Life at Stake' (not be be confused with the 1955 film with the same two titles), at about 57 mins, two characters meet in the Thameside Restaurant under Waterloo Bridge, left over from the Festival. This nice piece of modernist architecture remained until 1962.